Not I. I just make lots of leaves during warm weather and paint them during the Winter.
I have been wondering about skelton leaves that are used in scrapbooking. I use them for rollprinting metal and you get a nice imprint. Just haven't tried them in any cement work.

If it were just for my use, I would make them and paint them. I tried this method of preserving and it is ok but not something I might use for casting. Funny - I was looking over some old post and I must have asked the same question years ago.
I am trying some papercrete - I seems to take a little longer to cure. A little different to work with. Did a leaf cast too. Ordered Betty Mackey's - CD - hope to learn a lot.

Always looking for ideas for classes.
Have a nice TG --- Mike

Here is a link that might be useful: Mackey

I like to use vinyl cement patch to save leaves until I have time to make hypertufa. The vinyl cement patch is quick to make and easy to use. It also is very find and captures all the veins in the leaves. Then when I want to make a stepping stone I just wet the vinyl cement, apply a coat of additive and add hypertufa to the thickness needed for a stepping stone.

BTW - the leaves that I preserved with liquid glycerin turned out great. They are still preseved two months later and I bet they will last a long time. I have not tried them for conrete leaf casting , but they are plyable enough that with some sand support they might work.
Kar-garden - I use the vinyl concrete patch too, ( great for leaves) sometimes I dont have lots of time at the end of the season to mix up a batch and make leaves , so I was looking for an easy way to preseve some for a later winter date. Thanks for you suggestion - -

BTW Betty Macke has a great CD -